NAME
MooseX::XSAccessor - use Class::XSAccessor to speed up Moose accessors
SYNOPSIS
package MyClass;
use Moose;
use MooseX::XSAccessor;
has foo => (...);
DESCRIPTION
This module accelerates Moose-generated accessor, reader, writer and
predicate methods using Class::XSAccessor. You get a speed-up for no extra
effort. It is automatically applied to every attribute in the class.
The use of the following features of Moose attributes prevents a reader
from being accelerated:
* Lazy builder or lazy default.
* Auto-deref. (Does anybody use this anyway??)
The use of the following features prevents a writer from being
accelerated:
* Type constraints (except `Any`; `Any` is effectively a no-op).
* Triggers
* Weak references
An `rw` accessor is effectively a reader and a writer glued together, so
both of the above lists apply.
Predicates can always be accelerated, provided you're using
Class::XSAccessor 1.17 or above.
Clearers can not be accelerated (as of current versions of
Class::XSAccessor).
Functions
This module also provides one function, which is not exported so needs to
be called by its full name.
`MooseX::XSAccessor::is_xs($sub)`
Returns a boolean indicating whether a sub is an XSUB.
$sub may be a coderef, Class::MOP::Method object, or a qualified sub
name as a string (e.g. "MyClass::foo").
This function doesn't just work with accessors, but should be able to
detect the difference between Perl and XS subs in general. (It may not
be 100% reliable though.)
Chained accessors and writers
MooseX::XSAccessor can detect chained accessors and writers created using
MooseX::Attribute::Chained, and can accelerate those too.
package Local::Class;
use Moose;
use MooseX::XSAccessor;
use MooseX::Attribute::Chained;
has foo => (traits => ["Chained"], is => "rw");
has bar => (traits => ["Chained"], is => "ro", writer => "_set_bar");
has baz => ( is => "rw"); # not chained
my $obj = "Local::Class"->new;
$obj->foo(1)->_set_bar(2);
print $obj->dump;
Lvalue accessors
MooseX::XSAccessor will detect lvalue accessors created with
MooseX::LvalueAttribute and, by default, skip accelerating them.
However, by setting $MooseX::XSAccessor::LVALUE to true (preferably using
the `local` Perl keyword), you can force it to accelerate those too. This
introduces a visible change in behaviour though. MooseX::LvalueAttribute
accessors normally allow two patterns for setting the value:
$obj->foo = 42; # as an lvalue
$obj->foo(42); # as a method call
However, once accelerated, they may *only* be set as an lvalue. For this
reason, setting $MooseX::XSAccessor::LVALUE to true is considered an
experimental feature.
HINTS
* Make attributes read-only when possible. This means that type
constraints and coercions will only apply to the constructor, not the
accessors, enabling the accessors to be accelerated.
* If you do need a read-write attribute, consider making the main
accessor read-only, and having a separate writer method. (Like
MooseX::SemiAffordanceAccessor.)
* Make defaults eager instead of lazy when possible, allowing your
readers to be accelerated.
* If you need to accelerate just a specific attribute, apply the
attribute trait directly:
package MyClass;
use Moose;
has foo => (
traits => ["MooseX::XSAccessor::Trait::Attribute"],
...,
);
* If you don't want to add a dependency on MooseX::XSAccessor, but do
want to use it if it's available, the following code will use it
optionally:
package MyClass;
use Moose;
BEGIN { eval "use MooseX::XSAccessor" };
has foo => (...);
CAVEATS
* Calling a writer method without a parameter in Moose does not raise an
exception:
$person->set_name(); # sets name attribute to "undef"
However, this is a fatal error in Class::XSAccessor.
* MooseX::XSAccessor does not play nice with attribute traits that alter
accessor behaviour, or define additional accessors for attributes.
MooseX::SetOnce is an example thereof. MooseX::Attribute::Chained is
handled as a special case.
* MooseX::XSAccessor only works on blessed hash storage; not e.g.
MooseX::ArrayRef or MooseX::InsideOut. MooseX::XSAccessor is usually
able to detect such situations and silently switch itself off.
BUGS
Please report any bugs to
.
SEE ALSO
MooseX::XSAccessor::Trait::Attribute.
Moose, Moo, Class::XSAccessor.
AUTHOR
Toby Inkster .
COPYRIGHT AND LICENCE
This software is copyright (c) 2013, 2017 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under the
same terms as the Perl 5 programming language system itself.
DISCLAIMER OF WARRANTIES
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.